241Am(n,γ) cross section in the neutron energy region between 0.02 eV and 300 keV

Abstract

The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for a neutron capture cross section measurement on 241Am. The high granularity of the DANCE array (160 BaF2 detectors in a 4π geometry) enables an efficient detection of prompt gamma rays following neutron capture. The preliminary results on the 241Am(n,γ) cross section are presented from 0.02 eV to 300 keV. The cross section at thermal energy En = 0.0253 eV was determined to be 665±33 barns. Resonance parameters were obtained using the SAMMY7 fit to the measured cross section in the resonance region. Significant discrepancies were found between our results and data evaluations for the first three lowest lying resonances. The cross section for neutrons with En>l keV agrees well with the ENDF/B‐VII.0 and JENDL‐3.3 evaluations.